Need help with error log of Time Machine failed backup

[wlow3]

My parent’s iMac (2017, Mojave) Time Machine backup has been repeatedly failing. After several successful backups it will then say “error occurred while creating a backup folder.” I have to force eject it and physically unplug and replug it in to get it to work again for a while. I saw a Terminal command to get the error log (reprinted below). I don’t know enough about it to make heads or tails out of it. I do know that the backup is a folder structure .backupdb on an external Western Digital HD and not what I understand to be a network sparsebundle image so I’m not sure why it references a “matching sparsebundle”. Can anyone help me with what this is saying?

I saw someone online say that their issue was with a mismatch HostUUID but they were backing to a sparsebundle and they could get to com.apple.timemachine.machineid.plist to fix it but I would not know how to do this with .backupdb or if that is even the issue here.

Also, I had replaced their external HD so I don’t know whether that causes an HostUUID issue.

I’ve replaced mentions of my parent’s name with “[username]” for privacy.

Last login: Mon May 27 21:07:32 on console

macintosh:~ [USERNAME]$ log show --predicate 'subsystem == "com.apple.TimeMachine"' --info --last 25h | grep -F 'eMac' | grep -Fv 'etat' | awk -F']' '{print substr($0,1,19), $NF}'

2019-05-30 15:05:54 Failed to find matching sparsebundle in directory '/Volumes/My Backup', directory contents: (

2019-05-30 15:06:12 Starting automatic backup

2019-05-30 15:06:12 Failed to find matching sparsebundle in directory '/Volumes/My Backup', directory contents: (

2019-05-30 15:06:12 Failed to find matching sparsebundle in directory '/Volumes/My Backup', directory contents: (

2019-05-30 15:06:12 Backing up to /dev/disk3s2: /Volumes/My Backup/Backups.backupdb

2019-05-30 15:06:12 Error: (22) setxattr for key:com.apple.backupd.HostUUID path:/Volumes/My Backup/Backups.backupdb/[USERNAME]’ Computer size:37

2019-05-30 15:06:12 Backup failed with error 2: 2

 

[treekram]

I think the sparsebundle messages are misleading - confirm that by looking for a "file" (really a directory) with the ".sparsebundle" extension on the external HDD. If it's not there, then the messages are misleading - my guess is that it probably couldn't find the typical Backups.backupdb directory so it went searching for a sparsebundle.

You've done some searching over the web - they probably suggested that you remove any WD software that came with the external HDD. Also, make sure that in System Perferences->Energy Saver->Put hard disks to sleep when possible is disabled (at least to test this out).

Unfortunately, the Time Machine software is not maintained as well as it could be. If you can do manual backups (turn off automatic backups) and it works without fail there, you might want to consider doing that. Or you might want to consider 3rd-party clone software, some of which can do incremental backups. (Carbon Copy Cloner, Super Duper)